Honda Civic. Manual — part 450

Is the result OK?

YES - Go to step 32.

NO - Go to step 24.

24. Turn the ignition switch OFF.
25. Replace the EGR valve (see EGR VALVE REPLACEMENT ).
26. Reconnect all connectors.
27. Turn the ignition switch ON (II).
28. Reset the ECM/PCM with the HDS.
29. Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN

PROCEDURE ).

30. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or

neutral) until the radiator fan comes on, then let it idle.

31. Do the EGR TEST in the INSPECTION MENU with the HDS.
32. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0404 indicated?

YES - Check for poor connections or loose terminals at the EGR valve and the
ECM/PCM, then go to step 1. If the connections and terminals are OK, go to
step 34.

NO - Go to step 33.

33. Monitor the OBD STATUS for DTC P0404 in the DTCs MENU with the

HDS.

Does the screen indicate PASSED?

YES - Troubleshooting is complete. If any other Temporary DTCs or DTCs
were indicated in step 32, go to the indicated DTCs troubleshooting.

NO - If the screen indicates FAILED, go to step 1 and recheck. If the screen
indicates EXECUTING, keep idling until a result comes on. If the screen

2008 Honda Civic EX

2006-08 ENGINE PERFORMANCE EGR System (R18A1) - Civic (All Except Hybrid)

indicates OUT OF CONDITION, go to step 30.

34. Update the ECM/PCM if it does not have the latest software (see UPDATING

ECM/PCM ), or substitute a known-good ECM/PCM (see SUBSTITUTING
THE ECM/PCM ).

35. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or

neutral) until the radiator fan comes on, then let it idle.

36. Do the EGR TEST in the INSPECTION MENU with the HDS.
37. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0404 indicated?

YES - Check for poor connections or loose terminals at the EGR valve and the
ECM/PCM. If the ECM/PCM was updated, substitute a known-good
ECM/PCM (see SUBSTITUTING THE ECM/PCM ), then go to step 35. If
the ECM/PCM was substituted, go to step 1.

NO - Go to step 38.

38. Monitor the OBD STATUS for DTC P0404 in the DTCs MENU with the

HDS.

Does the screen indicate PASSED?

YES - If the ECM/PCM was updated, troubleshooting is complete. If the
ECM/PCM was substituted, replace the original ECM/PCM (see ECM/PCM
REPLACEMENT ). If any other Temporary DTCs or DTCs were indicated in step
37, go to the indicated DTCs troubleshooting.

NO - If the screen indicates FAILED, check for poor connections or loose terminals
at the EGR valve and the ECM/PCM. If the ECM/PCM was updated, substitute a
known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), then go to
step 35. If the ECM/PCM was substituted, go to step 1. If the screen indicates
EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF
CONDITION, go to step 35.

DTC P0406: EGR VALVE POSITION SENSOR CIRCUIT HIGH VOLTAGE

2008 Honda Civic EX

2006-08 ENGINE PERFORMANCE EGR System (R18A1) - Civic (All Except Hybrid)

1. Turn the ignition switch ON (II).
2. Check EGR VLS in the DATA LIST with the HDS. Is 4.88 V or more

indicated?

YES - Go to step 3.

NO - Intermittent failure, the system is OK at this time. Check for poor
connections or loose terminals at the EGR valve and the ECM/PCM.

3. Turn the ignition switch OFF.
4. Disconnect the EGR valve 6P connector.
5. Turn the ignition switch ON (II).
6. Measure voltage between EGR valve 6P connector terminals No. 2 and No. 3.

Fig. 7: Measuring Voltage Between EGR Valve 6P Connector Terminals
No. 2 And No. 3
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there about 5 V?

YES - Go to step 11.

NO - Go to step 7

NOTE:

Before you troubleshoot, record all freeze data and any on-
board snapshot, and review the general troubleshooting
information (see GENERAL TROUBLESHOOTING
INFORMATION ).

2008 Honda Civic EX

2006-08 ENGINE PERFORMANCE EGR System (R18A1) - Civic (All Except Hybrid)

7. Turn the ignition switch OFF.
8. Jump the SCS line with the HDS.
9. Disconnect ECM/PCM connector B (44P).

10. Check for continuity between EGR valve 6P connector terminal No. 2 and

ECM/PCM connector terminal B33.

Fig. 8: Checking Continuity Between EGR Valve 6P Connector Terminal
No. 2 And ECM/PCM Connector Terminal B33
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Go to step 18.

NO - Repair open in the wire between the ECM/PCM (B33) and the EGR
valve, then go to step 13.

11. Turn the ignition switch OFF.
12. Replace the EGR valve (see EGR VALVE REPLACEMENT ).
13. Reconnect all connectors.
14. Turn the ignition switch ON (II).
15. Reset the ECM/PCM with the HDS.
16. Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN

PROCEDURE ).

2008 Honda Civic EX

2006-08 ENGINE PERFORMANCE EGR System (R18A1) - Civic (All Except Hybrid)